Suspected Trump gunman had rifle with scratched-off serial number

The suspected gunman who authorities said may have tried to assassinate Donald Trump at his Florida golf course on Sunday left behind an AK-style rifle with a serial number that was at least partially obliterated, officials familiar with the investigation said, making it hard to quickly determine how the suspect procured the weapon.

Ryan Wesley Routh, 58, had a long history of criminal convictions, according to court records, including for more than one felony, which would have made it illegal for him to possess a firearm.

Authorities don’t believe Routh himself fired a shot, but he pointed the weapon through a fence, the officials said. At least one Secret Service agent, who was one or two holes ahead of Trump on the course, spotted Routh and fired at least four shots at him. Routh took off in a black Nissan but was captured soon after as he fled down I-95.

He is expected to make his first appearance in a federal court in Florida Monday morning.

Write to Sadie Gurman at sadie.gurman@wsj.com